There is no reward without effort! Even though dates tend to get more challenging as you advance through the game, they are definitely doable.
However, it's worth knowing that Date difficulty slightly increases with each Date you complete successfully. Subsequent plays of the same Date only increase the difficulty very marginally.
It only takes practice and keeping in mind that you need to increase your skills, like Romance and Beauty, in order to increase the number of points awarded by the bubbles. You can collect Cash easily by talking to the girls, as each right answer provides you with 30 in-game Cash. You can also increase the girls' personality stats and give them gifts in order to get more Cash when talking to them.
It only takes practice and keeping in mind that you need to increase your skills, like Romance and Beauty, in order to increase the number of points awarded by the bubbles. You can collect Cash easily by talking to the girls, as each right answer provides you with 30 in-game Cash. You can also increase the girls' personality stats and give them gifts in order to get more Cash when talking to them.